Let's do some math ..  Rounding examples of 7 random hypothetical purchases:
Case	Tag   Price	Sales   Tax %	Raw Total   Incl. Sales Tax	Rounded   to Penny	Rounded   to Nickel	Rounded   to Dime
Purchase #1	$118.40	6.695%	$126.3269	$126.33	$126.35	$126.30
Purchase #2	$36.37	3.215%	$37.5393	$37.54	$37.55	$37.50
Purchase #3	$197.27	5.575%	$208.2678	$208.27	$208.25	$208.30
Purchase #4	$226.73	5.618%	$239.4677	$239.47	$239.45	$239.50
Purchase #5	$78.32	13.728%	$89.0718	$89.07	$89.05	$89.10
Purchase #6	$209.61	7.455%	$225.2364	$225.24	$225.25	$225.20
Purchase #7	$90.89	9.816%	$99.8118	$99.81	$99.80	$99.80
7 purchase totals =	$957.59		$1,025.7217	$1,025.73	$1,025.70	$1,025.70